Why laptop? Laptops are warm, noisy, limited and slow. Forget the theoretical specs, everything on a laptop is underdimensioned compared to a proper stationary.
Am very happy with gaming stationary with 2 monitors. 64 GB RAM has very rarely been filled, but very handy when you need to explore. Am more comfortable, both physically and requirements-wise, than when I tried to cram everything into beasts of laptops, that always seemed limited in more than one ways and getting too warm.
Search for Linux-compatible laptops / laptops delivered with Linux on. You might need to try multiple distros in case one fails to detect all your hardware. Nowadays, I'd either go for Mint, Debian or Ubuntu, but many options out there. Realistically, probably need 2x hours to fix things compared to Windows, but it'll be yours to fix! However, you'll also get /4 the annoyances or less.
I keep my Windows in zoo, VirtualBox VMs. Easy to backup full images. A proper stationary means I can comfortably run 2 VMs simultaneously (1 for dev, 1 for prod). This means my trading platform is contained in minimalistic and predictable way, but also isolated from me tinkering with the main OS. Don't get me wrong, if Ninjatrader ran on native Linux, I'd probably just run it there, so more a workaround with benefits.
Plus, a good gaming PC easily runs all the Linux steam games.
If your computer don't run Linux properly, make sure you can return it for full refund. Usually not a problem, but we are at mercy of our vendors here and need to adress the issues of open standards, heterogenous free markets and healthy competition. Avoid anything proprietary, like iOS, Android and its ilk, that may later compromise your choices.
